Emirates Airline President Tim Clark says the carrier’s current order for the Airbus A350-1000 is “in limbo at the moment,” but he is not ready to step back from it.

The aircraft is “overweight and late,” Clark tells Aviation Week. “Let’s just see what she is like when she flies,” he adds. “At the moment there are issues.”

Emirates has placed orders for 50 A350-900s and 20 A350-1000s. Airbus has delayed the -1000’s entry-into-service of the -1000 by about two years to 2017, much to the chagrin of Middle East airlines, such as Emirates, Qatar Airways and Etihad Airways.

Emirates says the carriers were not consulted before Airbus decided on the delay, adding that the move was made mainly to accommodate upgrades and a thrust increase for the Rolls-Royce Trent XWB-97 engine.

Airbus Chief Operating Officer-Customers John Leahy says, “Emirates is a valued customer to us, and we are convinced our offering will deliver on their expectations.”

Clark hopes that the A350 will match the Airbus A380 program, which has exceeded performance expectations. “I kind of looked at the A380 as a late, overweight aircraft,” he says. “But when she flew, she was faster, more fuel-efficient and more aerodynamical and still is.” Clark points out that “the faster you fly [the A380], the more fuel-efficient she gets; when you fly at [Mach] 0.86 she is better than at 0.83.”

Also, Emirates has observed a very low degradation factor: The first aircraft delivered in 2008 would normally perform around 2.5-3% less efficiently than in the beginning, but according to Clark the degradation has been only around 1%. Also, Airbus and Emirates have taken a combined 5 tons out of the aircraft’s weight.

“Now roll that forward into the A350–it is late and overweight. But we got a pleasant surprise with the A380, maybe we also get a pleasant surprise with the A350-900 and -1000,” Clark says.

Leaving performance issues aside, the A350-900 “is starting to look a bit marginal to us because of size,” he adds. “Gauge is the way we grow, you cannot get any more aircraft into the Dubai hub.”

Clark also tells Aviation Week he considered buying a stake in Air Berlin a year ago, about the same time as rival Etihad Airways was negotiating its 29.2% stake in the German airline.

Clark says that buying into Air Berlin would have been “not without risks”, and would have required more management involvement that Emirates deemed acceptable.

“In the end we felt we were strong enough to support the amount of flights we are doing [into Europe],” Clark says. “So why would you throw €500 million [$641 million] at it?”

He concedes, however, that there might be “some measurable benefit for Etihad because the flows are coming through.”

Emirates’ analysis of Air Berlin’s finances a year ago came to the conclusion that “the cash position was looking shaky, but the business plan with regards to fleet and labor was salvageable,” says Clark.

“For me it was salvageable.”